The diagnosis of depression in drug dependent individuals has been made with increasing frequency over the past several years. This depression may be primary and precede involvement with drugs or may be secondary and consequential to the effect of drug use and the accompanying lifestyle. In either case the symptoms of depression are distressing to the patient and may well contribute to early termination of treatment and a return to the uncontrolled use of drugs. This study will investigate the impact of doxepin HC1, (a tricyclic compound with combined antidepressant/antianxiety effects) on a group of depressed narcotics addicts on methadone maintenance and multiple substance abusers in an outpatient setting. The diagnosis of depression will be made by clinical interview and scores on two standard depression rating scales: the Hamilton Depression Rating Scale and the Beck Depression Inventory. Subjects will be randomly assigned to doxepin treatment or placebo control group. All other aspects of treatment will be the same for each group. Double blind procedures will be followed. Subjects will be followed for a minimum of six months and maximum of 18 months in each group. Depression rating scales and the Social Adjustment Scale Self-Report will be administered regularly throughout the study period. Outcome criteria will include symptomatic improvement in depression as measured on standard scales, positive ranges in social adjustment, and retention in treatment.